A conventional fastening device is shown in FIGS. 7 to 9, and generally includes a cap 4 which is rotated to one direction to fasten the strip of shoelace. The cap 4 includes inner gear 41 and outer gear 42, and both of which are rotated simultaneously when the cap 4 is rotated. The inner gear 41 is engaged with the gear 51 on the spool 5 such that the strip of the shoelace is wrapped around the spool 5 and received in the accommodation space 52 of the spool 5. The outer gear 42 is engaged with the ratchet teeth 61 on the ratchet ring 6 to ensure that the spool can only be rotated in one direction and to prevent the strip of the shoelace from loosened. When rotating the cap 4, the ratchet ring 6 is moved up and down by the flexible legs 62 connected to the underside of the ratchet ring 6 such that the ratchet teeth 61 is engaged with the outer gear 42 to ensure the rotation is stable and smooth. When loosening the strip or the shoelace, the cap 4 is pulled upward so that the shaft 7 in the hole of the base 8 is moved upward a distance while the positioning member 83 in the pivotal part 82 is engaged with the lower groove 71 of the shaft 7 to avoid the shaft 7 from being pulled out from the pivot part 82. In this status, the inner gear 41 is disengaged from the gear 51 on the spool 5, and the outer gear 42 is disengaged from the ratchet teeth 61 of the ratchet ring 6, so that the cap 4 is rotated without driving the spool 5. The strip or the shoelace is then able to be loosened.
However, when the strip or the shoelace is too much tightened, the user has to pull the cap 4 upward to disengage the outer gear 42 from the ratchet teeth 61 of the ratchet ring 6 so as to loose the strip or the shoelace. Once the action is done, the user has to re-tighten the strip or the shoelace again and do that carefully to avoid from tighten the strip or the shoelace too much. In other words, there lacks a way to loose the strip or the shoelace a little hit without the need to pull the cap upward.
The present invention intends to provide a stepless fastening device which allows the users to rotate the cap in opposite direction to steplessly loosen the strip or shoelace a little bit without the need to pull the cap upward.